Question

How do you write an equation of a line going through (3,-1) perpendicular to y=4x+1?

Answer 1

`x+4y+1=0`

Explanation:

gradient of the line `y=4x+1` is `4`

Perpendicular means that the gradient of the line perpendicular to the line `y=4x+1` is `-1/4` because the product of the two gradients must equal to `-1` ie `m_1m_2=-1`

Using point gradient formula,

`(y+1)=-1/4(x-3)`

`4y+4=-x+3`

`x+4y+1=0`